Killer Whales
Southern Residents
The Southern Resident Killer Whales (SRKWs) are a specific ecotype of killer whales whose territory comprises the Salish Sea around southern Vancouver Island, extending from Georgia Strait in the east and along the pacific coast to the west. The North Pacific resident killer whale population was originally listed as threatened under the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). In 2001 the population was subdivided into three populations and the SRKWs were added as a Schedule 1 species under the Species at Risk Act (SARA) and listed as endangered.
The Southern Residents are comprised of 75 whales belonging to three pods: J pod, L pod and K pod. Currently L pod is the largest with 34 individuals followed by J pod with 25 individuals and K pod being the smallest with 16 individuals. Each pod has a slightly different range, driven by the search for Chinook but generally the SRKWs range from Haida Gwaii to Monterey Bay. Killer whales will typically travel with their whole pod or with their immediate families in smaller matrilines. The SRKWs, like other toothed whales can be quite vocal. Each pod has its own unique dialect which is made up of approximately a dozen discrete calls. A pods dialect is likely passed down by older females and is highly stable through time. The SRKWs also employ shorter echolocation clicks to navigate and locate prey.
Since 1998, 48 SRKWs have been born and survived, and 82 have gone missing or have been confirmed deceased with 10 of these deaths/disappearances occurring in the last five years. One of the biggest losses felt by the SRKWs in recent years occurred in 2017 with the passing of Granny (J2), who was estimated to be 105 years old at the time of her death and was the oldest known killer whale. The summer of 2018 also brought heartbreak for the pod when Tahlequah (J35) lost her second calf. She pushed her dead calf on her head for 17 days, covering over 1,000 miles and drawing international attention to the plight of the SRKW who had not had a successful birth in three years.
The SRKW population is currently facing a myriad of threats and are still dealing with the repercussions of the live captures that occurred in 1965-75, where at least 13 whales were killed and 45 were delivered to aquariums. There are three primary threats to the SRKW population: prey reduction, pollution, and vessel disturbance, all of which are human caused threats. The loss of Chinook ensures the continuing decline of this population, due to Chinook comprising approximately 80% of the SRKWs diets. The SRKWs like all other marine mammals are negatively affected by environmental toxins, including PCB’s. PCB’s have been shown to alter killer whale behavior, damage their immune system and harm reproduction. Vessels can cause disturbance in two ways, physical and acoustic. Acoustic disturbance interferes with echolocation, negatively impacting the whales' ability to hunt, communicate, and navigate. Acoustic disturbance can come from engine noise, depth sounders, and even drones. Physical disturbances create obstacles and hazards that require the whales to expend critical energy to avoid and put them at risk for vessel strike. Physical disturbances interrupt natural behaviours and distract whales from critical activities like foraging/eating and social interactions. All vessels, even human powered crafts, can pose threats to these whales, from cruise ships and tankers to smaller crafts such as whale-watch vessels, small recreational vessels, Sea-Doos, and kayaks. We are all influencing the habitat of the SRKWs and it’s important as responsible boaters to do our part.
Northern Residents
The Northern Resident Killer Whales (NRKWs) are a specific ecotype of killer whales whose territory comprises northern Vancouver Island, along the sheltered inlets of the British Columbia’s central and north coasts and have been seen in southeast Alaska in the winter. The North Pacific resident killer whale population was originally listed as threatened under COSEWIC. In 2001 the population was subdivided into three populations and the NRKWs were added as a Schedule 1 species under SARA and maintained their threatened status.
The Northern Resident population consists of three clans (A, G & R), 34 matrilines and over 200 individuals. Each clan is composed of multiple matrilines and share a collection of common calls. This population, like the SRKW’s was impacted by the live capture fishery during 1964-1973 where at least 14 individuals were removed. The NRKW population was originally censused in 1974 with a population estimate of 120 whales, the population steadily grew to a peak of 220 individuals in 1997. Between 1997 and 2002 the NRKWs experienced a population decline from 1997-2002 but rebounded and has been steadily increasing with a population of 309 in 2017.
The NRKWs are an intrinsic part of the fabric of life in Johnstone Strait and the communities surrounding it. The Robson Bight (Michael Bigg) Ecological Reserve (RBMBER) established in 1982, protects a critical habitat for the NRKWs. The reserve encompasses critical foraging habitat and at least six rubbing beaches. For reasons not yet wholly understood, the NRKWs routinely and regularly rub on the pebbles in the Reserve which is a highly ritualized social behaviour known to very few killer whale populations. More than 90% of the NRKWs observed in Johnstone Strait visit the rubbing beach and spend upwards of 10% of their time there.
The threats posed to their survival are the same as those that have pushed the SRKWs towards extinction. Their protection from both physical and acoustical disruptions caused by vessel traffic (as well as from pollutants and toxins and loss of prey) is critically important if they are not to suffer a similar fate as the SRKWs and become endangered. Mitigating these human-caused dangers to the NRKWs is therefore urgently important.
Transient (Bigg’s) Killer Whales
Transient killer whales, also known as Biggs killer whales, range from Alaska to southern California and can be found in B.C. waters year-round. Transient killer whales were assessed as threatened by COSEWIC and SARA listed as Schedule 1 with the same status in 2003. Transient killer whales do not interbreed with the resident populations, and recent evidence has shown they have at least 750,000 years of separation.
Transient killer whales differ from the resident populations in both morphological and behavioural ways. Transient killer whales tend to have a pointier dorsal fin than residents and they always have a closed saddle patch. Transients also predate primarily on marine mammals including, harbour seals, sea lions, porpoises, dolphins and even some young baleen whales. They rely less on vocalization and echolocation than the residents when hunting as to not alert their prey. They often engage in highly co-operative and coordinated efforts during a hunt, which can take anywhere from just minutes to several hours. Transients employ extremely dramatic surface activities during a hunt, punting prey into the air, striking it with their tails or swimming on top of their prey to drown it.
Their population is currently estimated at 350 individuals and growing at a rate of 4.1% annually. The recent growth of the population has been attributed to the return of harbour seal populations in the Salish Sea, which have reached healthy levels for the first time since the Marine Mammal Protection Act was implemented in 1972. Transient social structure also differs from the residents, they still travel in matrilines, but mature daughters are more likely to break off from their mothers forming many small matrilines.